Published 8 August 2023
(Revised version 08/08/2023 to take into account recent developments. Originally published November 2022) Role of lawyers has been fundamental to the creation, development and reformation of the Investor-State Arbitration (ISA) system. This article conceptualizes the role of private lawyers acting as counsels and arbitrators in ISA as an epistemic community bound together in their shared beliefs about the ISA system and fostering the growth of a common culture of arbitration. As arbitrators and counsels, private lawyers continue to impact the development of ISA by developing substantive principles of international investment law. There is evidence to suggest that international investment law would have developed differently had interpretive discretion been exercised by other individuals than ones who were appointed in a given case. Their role raises a number of important questions: does the participation of ‘elite’ private lawyers with intrinsic financial interest in supporting arbitration affect the legitimacy and credibility of ISA as a dispute resolution process involving public-policy stakes? If yes, how should the system of ISA be reformed and whether the reforms at the ICSID and UNCITRAL adequate? This article explores the power-sharing between individual lawyers who belong to the profession of arbitration and (host and home) States and the implications and spill-over effects of private power in public realm in the ISA context.